1. Clinical Overview
Trifluoperazine is a high-potency, first-generation (typical) antipsychotic of the phenothiazine class, specifically a piperazine derivative. It is a potent dopamine D2 receptor antagonist with significant antiemetic and antipsychotic properties. In the Indian context, it is widely used for the management of schizophrenia, psychotic disorders, and severe anxiety, though its use has declined with the advent of atypical antipsychotics due to a higher risk of extrapyramidal side effects (EPS).
| Onset | Duration | Bioavailability |
|---|---|---|
| Oral: 1-2 hours for antiemetic effect; Antipsychotic effect may take several days to weeks for full manifestation. | Approximately 4-6 hours for antiemetic effect; Antipsychotic effect is sustained with chronic dosing. | Approximately 40-50% after oral administration due to significant first-pass metabolism. |
2. Mechanism of Action
Trifluoperazine exerts its primary antipsychotic effect by blocking postsynaptic dopamine D2 receptors in the mesolimbic and mesocortical pathways of the brain. Its antiemetic action is due to blockade of D2 receptors in the chemoreceptor trigger zone (CTZ). It also has moderate anticholinergic and alpha-1 adrenergic blocking activity.
3. Indications & Uses
- Schizophrenia (acute and chronic psychosis)
- Severe anxiety and tension states (short-term management)
- Severe nausea and vomiting
4. Dosage & Administration
Adult Dosage: Psychosis: Initial: 2-5 mg twice daily. Maintenance: 15-20 mg/day, may increase up to 40 mg/day in hospitalized patients. Severe Anxiety: 1-2 mg twice daily. Max: 6 mg/day. Antiemetic: 1-2 mg twice daily.
Administration: Administer orally with or without food. To minimize GI upset, take with food or milk. Avoid abrupt discontinuation. Tablets should be swallowed whole with a glass of water.
5. Side Effects
Common side effects may include:
- Drowsiness/sedation
- Dry mouth
- Blurred vision
- Constipation
- Dizziness (postural hypotension)
- Extrapyramidal Symptoms (EPS) - Akathisia, dystonia, parkinsonism
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Levodopa | Mutual antagonism; reduces efficacy of levodopa in Parkinson's. | Major |
| Other CNS Depressants (Alcohol, Opioids, Benzodiazepines) | Additive CNS depression, respiratory depression, hypotension. | Major |
| Anticholinergics (Trihexyphenidyl, Benztropine) | Increased anticholinergic side effects (constipation, urinary retention, confusion). | Moderate |
| Antihypertensives | Potentiates hypotensive effect. | Moderate |
| QT-prolonging drugs (Amiodarone, Sotalol, TCAs, Macrolides) | Increased risk of torsades de pointes. | Major |
| CYP2D6 Inhibitors (Fluoxetine, Paroxetine, Quinidine) | Increased trifluoperazine plasma levels, risk of toxicity. | Moderate |
7. Patient Counselling
- DO take exactly as prescribed by your doctor.
- DO report any involuntary muscle movements, restlessness, or fever immediately.
- DO rise slowly from sitting/lying position to avoid dizziness.
- DONT stop taking the medicine suddenly without consulting your doctor.
- DONT consume alcohol in any form.
- DONT drive or operate machinery if you feel drowsy.
- DO use sunscreen and protective clothing as you may become more sensitive to sunlight.
8. Toxicology & Storage
Overdose: Symptoms range from CNS depression (coma, respiratory depression) to CNS stimulation (seizures, agitation). Severe extrapyramidal reactions, hypotension, cardiac arrhythmias (QT prolongation), hyperthermia, and anticholinergic crisis (dry skin, hyperthermia, ileus) may occur.
Storage: Store below 30°C. Protect from light and moisture. Keep the tablet in the blister strip until use. Keep out of reach of children.